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Need your help! Prius 4 tire information spreadsheet

Discussion in 'Gen 4 Prius Main Forum' started by kitkit201, Jan 27, 2016.

  1. Maxwell61

    Maxwell61 Active Member

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    mmmm... so from another thread, it seems that Toyota wants you to inflate the 15" at the hypermiling pressure of 36" only if you have a tire 89S (defined as "Type A"), not if your tire is 91H. And we know the effect of extra pressure on mileage.

    So i guess if they delivered some Two ECO with tires marked 91H, they are not fulfilling some kind of promise about the mileage, due to the lower pressure on delivery.

    Looking at the spreadsheet, for the time beeing the Two Eco seems to be fitted with the Ecopia 422 Plus: can some owner double check the speed/load index on the wall? And it would be interesting to know the same for the Nanoenergy A29-

    [​IMG]

    PS: According to Tire Rack, the Ecopia 422 Plus 195/65/R15 only exists in 91H version, so actually the Two ECo should'nt be allowed to run the 36 psi pressure...

    Bridgestone Ecopia EP422 Plus (H- or V-Speed Rated)
     
    #21 Maxwell61, Feb 11, 2016
    Last edited: Feb 11, 2016
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  2. JamesBurke

    JamesBurke Senior Member

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  3. Maxwell61

    Maxwell61 Active Member

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    Thanks for clarifying, i've missed it. Now it would be interesting to know if the Non-Touring Non-Eco have the same tires (i mean the same speed/load parameter) of the Two ECO.

    Thanks for this, for us europeans. Bad news, the EP150 is an old tire class B on RR and B for wet. The same Bridgestone have the EP001S A for RR and A for wet, difficult to understand Toyota choice. In terms of FE, the difference btw an A class and a B class could be substantial. We have quite a few Prius and Auris HSD on the forum , using aftermarket EP001S and they go like a charm.

    Whether one can extrapolate if the same class would apply to the 422 Plus i do not know.
    For the Turanza T002 i could'nt find any european class.
     
  4. bisco

    bisco cookie crumbler

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    maxwell, what chart is that showing type b, that they've gone to 32psi all around in the 15", including the spare, in your post #21?
     
    #24 bisco, Feb 11, 2016
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  5. JamesBurke

    JamesBurke Senior Member

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    That would indicate a near balanced axle ratio when full of fuel and with two 150lb passengers in the front seats and one 150lb passenger in a back seat that give the greatest load to a wheel. These are Fed code requirements.

    Higher psi for the 89S tires because they have lower load to inflation pressure values than the 91H. 1279@max vs 1356@max. Pressure to load is close to linear for these tires. Comparing Bridgestone. Variation in curb weights between models not that significant compared GVWR or the load given above.

    Type B gets full sized spare?
     
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  6. krmcg

    krmcg Lowered Blizzard Pearl Beauty

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    IMG_0410.JPG
     
  7. Maxwell61

    Maxwell61 Active Member

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    Sorry krmcg, i can't see in the pic if they are 91H o 89S....
     
  8. krmcg

    krmcg Lowered Blizzard Pearl Beauty

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    89S
    FullSizeRender3.jpg
     
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  9. Maxwell61

    Maxwell61 Active Member

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    Right, so according to Toyota you have on a Prius FOUR a (non standard supply Toyo) Type A (89S) as indicated by Bridgestone press release.

    If we guess that the 36psi 89S is more fuel efficient than the 91H run at 32psi, tires cannot be the reason of such a large gap in FE btw 2ECO and 2,3,4.....
    Then, look for software and engine tuning (or whatever BIG) for the ECO miracle, beeing the remaining known differences not really a way to justify the gap.

    According to Bridgestone , all the non-touring Prius US should have the 15" 89S at 36 psi.

    [​IMG]

    PS: As a side note, just some new NEDC and info for Prius IV EU came up. We don't have any ECO nor any trim using the Li-Ion, only Ni-Mh.

    The NEDC values are given for the 15" and 17" separateley tested:

    15" city/HWY/combined 2,9/3/3,1 L/100km
    17" city/HWY/combined 3,3/3,3/3,3 L/100km

    So, a 6,5% decrease in FE is measured for the 17".
    Absolute values are absolute b***shit , but the difference, for city and medium speed, should be reliable. I do repeat, hypermilers better stay away from Tourings.....
     
    #29 Maxwell61, Feb 11, 2016
    Last edited: Feb 11, 2016
  10. JamesBurke

    JamesBurke Senior Member

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    For 15" USA gets the type A Bridgestone 422 89S or Toyo NEA29 89S. Europe and Japan are getting the type B Ecopia EP150 91x or ? with a lower psi. That's what I see anyway. What's supposed to be on the 2Eco again?
     
  11. bisco

    bisco cookie crumbler

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    but on page one, the door jamb pic shows 36/35? are we talking usa only?
     
  12. JamesBurke

    JamesBurke Senior Member

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    2 Eco placard picture shows 39 psi front 36 psi rear. This different from the table. Could the 2 Eco also have the 640 vs. the 540 treadware rated 422's? Are there variants of the Toyo A29?
     
  13. Maxwell61

    Maxwell61 Active Member

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    No other option than the EP150 91H for the 15" in Eu, but the car is not yet for sale, so we don't know if it ends up with some other tire.
    From the Bridgestone Press Release, is not quite clear if Bridgestone got some exclusive supply.....

    That's the point of confusion. Toyota Prius owner manual does'nt mention the 39 psi option.
     
  14. JamesBurke

    JamesBurke Senior Member

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    The placard on the door jam is the law here. Who knows when the manual was created.
    Higher tire psi plus higher treadware/lower rolling resistance tire variant plus -70lbs. equals how much MPG gain?

    Just because I can: Europe Ships I'm pretty sure
    HAMBURG HIGHWAY
    EGSUZ 2016-02-12 20:00

    BOHEME
    EG SUC 2016-02-17 18:00

    CAPE TOWN HIGHWAY
    EGSUZ 2016-02-29 21:00
     
  15. Maxwell61

    Maxwell61 Active Member

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    Needs a Two ECo owner that report the speed/load parameters and threadwear; i would start to question me only then..
    You daredevil spy :D
     
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  16. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Thanks!
    Tire model psi rev/mile
    1 P195/65R15 89S 36 833 turns slowest 1.19%; true MPG > indicated
    2 P195/65R15 91H 32 843
    3 P215/45R17 87V 33 845

    Bob Wilson
     
  17. wjtracy

    wjtracy Senior Member

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    When someone gets a chance, give a management summary:
    Does there seem to be any difference in 2 eco tire sub-type or pressure that could account for +4 MPG?
     
  18. bwilson4web

    bwilson4web BMW i3 and Model 3

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    There are two effects:
    • tire pressure - increasing pressure always improves MPG although 4 psi seems 'modest' and not enough by itself.
    • tire circumference - this is a type of 'over-drive'. For the EPA tests, true distance is measured by the dyno. The indicated speed and MPG could be off by 1.19%. Hummm, where have we seen that before . . . Oh yea, Wayne Gertes early report.
    If Wayne did his testing right, he used a GPS coupled, OBD recorder, the closest to a true metric without adding a 5th wheel and precision fuel flow meter. But we'll have to discuss this technology another day and a different forum. <GRINS>

    Bob Wilson
     
  19. Mendel Leisk

    Mendel Leisk Senior Member

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    A tire pressure change of 4 psi is trivial, any mpg difference would be obscured by other variables, ie: wind, temperature, traffic.
     
  20. bisco

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    yes, but those variables would affect the non eco numbers as well.